Bionomics of Aedes Aegypti and Aedes Albopictus in relation to dengue incidence on Penang island and the application of sequential sampling in the control of dengue vectors
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Date
2007
Authors
Chooi Khim, Phon
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Abstract
A study was carried out to determine the distribution of two dengue vectors, Aedes aegypti and Aedes albopictus in Kampung Paya Teluk Kumbar (rural area), Kampung Baru Sungai Ara (suburban area), and Lorong Mahsuri (urban area), in Penang, Malaysia from October 2003 to November 2004. A total of 60 ovitraps (30 indoor and 30 outdoor) were placed in each location. Intraspecific and interspecific competitions among these mosquitoes were studied under laboratory conditions using the Lorong Mahsuri strain. The relationship between mosquito abundance, physical parameters, and dengue incidence in all three areas were analyzed using linear regression. The potential use of presence-absence sequential sampling for making control decision was tested. The results showed that Aedes albopictus was the dominant species, both indoor and outdoor in Penang Island. Aedes aegypti prevails in the urban settlement (Lorong Mahsuri), and prefers to breed indoor. Furthermore, Aedes aegypti has begun to spread slowly to the southwestern part of Penang Island. Aedes albopictus showed greater survivorship compared to Aedes aegypti when food availability is low and larval density is high. The competitive advantage of Aedes albopictus in situation of limited resources could be the reason for the dominancy of this mosquito in Penang Island. The previous two months rainfall seems to give a constant positive correlation effect on the Aedes population in the Lorong Mahsuri and Kampung Paya Teluk Kumbar. In Kampung Baru Sungai Ara, rainfall had a significant positive correlation effect on the current monthly dengue cases. In Kampung Baru Sungai Ara and Lorong Mahsuri, mosquito abundance had a positive correlation effect on the dengue cases for the following one month. Aedes albopictus gave a better correlation with the incidence of dengue cases compared to Aedes aegypti. The density estimation of Aedes egg population was made using the presence-absence sequential sampling, in Lorong Mahsuri and Kampung Baru Sungai Ara. In Kampung Baru Sungai Ara, a population estimation using 60 ovitraps showed that when positive ovitraps were 75.00% or less, no control is needed; at 83.33% or higher positive ovitraps, control is needed. While in Lorong Mahsuri, when 73.33% or less ovitraps were positive, no control is needed, but when 83.33% or higher was positive, therefore control is needed.
Description
Master
Keywords
Biological Science , Aedes Aegypti , Aedes Albopictus